metamorphic
Epidote-rich rock (likely epidotite or altered basalt)
Epidote, Ca₂(Al,Fe³⁺)₃(SiO₄)₃(OH); possibly epidote-bearing mafic rock
AI-generated identification · may be incorrectHardness about 6–7 Mohs; pistachio-green to yellow-green, dull to vitreous luster, granular massive texture, and no obvious cleavage in the specimen. Epidote commonly forms monoclinic crystals, though this sample appears fine-grained and rounded.
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Physical properties
Hardness about 6–7 Mohs; pistachio-green to yellow-green, dull to vitreous luster, granular massive texture, and no obvious cleavage in the specimen. Epidote commonly forms monoclinic crystals, though this sample appears fine-grained and rounded.
Formation & geological history
Epidote forms during low- to medium-grade metamorphism and hydrothermal alteration of basalt, gabbro, and calcium-rich rocks. Its exact age cannot be determined from the photograph; it occurs in rocks of many geological ages.
Uses & applications
Used mainly as a collector mineral, lapidary material, and occasional ornamental stone; epidote is not a major industrial or construction material.
Geological facts
The vivid pistachio-green color is characteristic of iron-bearing epidote. The specimen may also contain chlorite, actinolite, feldspar, or quartz, so precise identification requires hardness, streak, and laboratory testing.
Field identification & locations
Common in metamorphic belts and hydrothermal veins worldwide, including Austria, Pakistan, Norway, Mexico, and the United States. Look for green grains, glassy cleavage faces, and hardness above glass; a polished surface or testing would improve confidence.
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